Burglar-alarm



(No Model.)

C. H. PRATT.

BURGLAR ALARM.

Patented Mar. 21, 1893..

Ww. M

UNITED STATES PATENT OFFICE.

CHARLES H. PRATT, OF LANCASTER, PENNSYLVANIA.

BU RG LAR-ALARM.

SPECIFICATION forming part of Letters Patent N0. 493,647, dated March 21, 1893.

Application filed October 3, 1892. Serial No. 447,611. (No model.)

To all whom, it may concern:

Be it known that I, CHARLES H. PRATT, a citizen of the United States, residing in Lancaster, in the county of Lancaster and State of Pennsylvania, have invented certainlmprovements in Burglar-Alarms, of which the following is a specification.

This invention relates to improvements in that class of devices whereby an alarm is caused to sound upon the opening of a door; and the object of the invention is first, to provide a cheap portable alarm by which the opening of a door near which it is placed will be indicated, and second, to construct the alarm so that it need be in no wise connected with the door.

The invention consists in the construction and combination of the various parts, as hereinafter fully described, and then specifically pointed out in the claims.

In the accompanying drawings, which form a part of this specification, Figure l is a side elevation of a bell embodying my invention shown in position to give an alarm upon the opening of the door. Fig. 2 is a top view ot' the same, the gong being removed to show the construction by which the mechanism for actuating the clapper is locked; and Fig. 3 is a similar view showing said mechanism unlocked. Fig. 4 is an enlarged plan view ofthe heel or base F.

Similar letters indicate like parts throughout the several views.

Referring to the details of the drawings, A represents a door, the opening of which is to be indicated by the sounding of the alarm. The alarm consists of a shell or hollow base, B, of any desirable shape suitable for the purpose. In the cavity of shell B there is located a clock or other mechanism such as is used for actuating the clappers of bells covered by a plate b, through which passes a post C, on the top of which is removably secured the gong bell D. The upper surface of the plate b is on the same plane with, or raised somewhat above, the plane of the upper rim ct of base B; and the bell D is held at such elevation that the lower rim thereof is raised somewhat above rim d, thus leaving an opening or passage between the adjacent rims of the base and bell. Through this opening there passes a push-bar E having a heel or base F that rests longitudinally on plate l); the heel is wider than the bar but both are of the same thickness. The outer end of the bar has a crescent shaped head M formed thereon with the horns m turned outward. A longitudinal slot e in bar E is engaged by a pin or stud b on one end of plate b, the top of said stud having a head that laps the sides ot' the slot and prevents upward movement of the bar. The inner end of heel F is bifurcated to form jaws f, which embrace post C, engaging grooves d, on opposite sides of said post, whereby the inner end ot' the head is held down on plate b.

Between stud b and post C a vertical rock` shaft G passes up through plate b and an opening, g, in heel F, to the upper end of which shaft is attached the bell clapper H. There is also a tongue h rigidly attached to shaft G that rests on plate b in opening g of head F and vibrates with the movement of said shaft. The end h of the tongue is reduced and is adapted to engage a recessR in one end of opening g. The mouth r of recess R is of suflicient width to readily receive the reduced end of tongue h, but the walls r of said recess iiare outward from the mouth, so as to reduce the friction between said: walls and the tongue to the minimum as the latter is received in and freed from the recess.

When the mechanism for operating the clapper is clock-work there is a device for winding up the same located in a recess or hollow in the bottom of base B. This is not shown in the drawings, as such devices are numerous and well known in connection with similar mechanisms, and as it is not material to the invention.

When prepared for service the push-bar E is drawn outward with the end of tongue h engaged by recess R to lock the mechanism which actuates the clapper. The alarm or bell is then placed on the lioor near the door with the head M adjacent thereto, or the horns m may preferably rest against the door,upon openin g which the slightest push against head M drives back bar E, releases tongue h from recess R and unlocks the operating mechanism. The head M is formed on bar E to prevent the alarm being pushed aside from beneath the door. With the horns m abutting against the door it is almost impossible to IOO lro

push the alarm aside by inserting anything under said door Without pressing one of the horns against the same with sufficient force to set off the alarm, whereas if the pushbar had a plane end this might readily be done.

I do not limit myself to the use of any particular mechanism for sounding the bell; neither do I restrict myself to the particular construction and arrangement of the pushbar, nor the means by which it is secured in place.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. The combination, with a bell, of a rockshaft carrying` a clapper mechanism for actuating the rock-shaft, a tongue attached to said l shaft, and a push-bar having a recess therein which is engaged with and disengaged from said tongue by the movement of the push-barge said recess having the walls thereof daring inward from its mouth, substantially as and for the purpose specified.

2. The combination, With a bell, of a rockshaft carrying a clapper, mechanism for actuating the rock-shaft, a tongue attached to said shaft and having a reduced end, a push-barhaving a recess therein which is engaged with and disengaged from said tongue by the movement of the push-bar, said recess having the Walls thereof aring inward from its mouth, substantially as and for the purpose specified.

3. The combination, with a bell, of a pushbar having an opening therein and jaws formed on the end thereof, a rock-shaft pass-V ing through the opening in the push-bar and carrying a clapper, a tongue attached to the rock-shaft and located in the opening in the push-bar, said tongue being engaged with and disengaged from a recess in one end of said opening by the movement of said bar, and a post having grooves engaged by the jaws of the push-bar, substantially as and for the purpose specified.

4. The combination, with a bell, of a rock shaft carrying a clapper, a push bar having an opening through which the rock-shaft passes and a slot engaged by a headed stud or pin, and a tongue attached to the rock-shaft and located in the openingin the push bar through which the rock-shaft passes, said ton gue being engaged with and disengaged from a recess in one end of said opening by the movement of the push-bar, substantially as and for the purpose specified.

5. The combination, with a bell, of a pushbar having an opening therein and provided with a slot engaged by a headed stud or pin,

l a rock-shaft passing through said opening and carrying a clapper, jaws formed on the inner end lof the push-bar, a tongue attached to the rock-shaft and located in the opening .in the push-bar, said tongue being engagedwith and disengaged from a recess in one end of said opening by the movement of the push-bar, and a post having grooves engaged by the jaws on the push-bar, substantially as and for the purpose specified.

CHARLES Il. PRATT.

Witnesses:

GEO. A. LANE,

WM. R. GERHART. 

